Method of and apparatus for accordion folding of endless webs

ABSTRACT

A method of and an apparatus for the folding of paper to produce accordion folds in which the web is engaged at each second groove previously formed in the web and moved at a speed matched to the feed of the web upwardly along a linear path and downwardly along an arcuate path so as to produce the accordion fold.

FIELD OF THE INVENTION

[0001] Our present invention relates to a method of and to an apparatus for the accordion folding of endless webs of foldable material, especially paper and, more particularly, webs which have equidistant grooves subdividing the web into segments or panels and wherein the web is advanced at a certain speed and as a result of the accordion folding, each two panels connected by a groove at a fold, lie one upon the other.

BACKGROUND OF THE INVENTION

[0002] Certain materials, generally referred to as endless webs or continuous webs, must be folded for handling, storage or the like, especially if the material is such that it cannot be effectively bent and thus stored in a roll without damage. This is the case, for example, with single layer or multilayer corrugated paper and like materials. Such webs are generally collected in the form of accordion-folded products.

[0003] In the past it has been the practice to form fold lines along the transverse grooves of the web and to bend the web at the fold line by hand. The upper panel is then pressed down upon the lower panel. The bending of the web to form the fold is usually assisted by driving a bar of wood against the web in the region of the groove.

[0004] Obviously this approach requires considerable effort and personnel. Furthermore, an exact folding along a groove cannot always be ensured so that, as a general matter, the accordion folding can be somewhat ragged or of insufficient precision.

OBJECTS OF THE INVENTION

[0005] It is therefore the principal object of the present invention to provide an apparatus and a method of forming accordion-folded webs whereby the earlier drawbacks can be avoided and the accordion folding of a continuous web can be effected automatically and with a high degree of precision.

[0006] Another object of the invention is to provide a method of according folding a continuous web in which the accordion-folded product has a high degree of reproducibility and accuracy.

[0007] Another object of the invention is to provide an improved apparatus for accurately according folding a continuous web.

SUMMARY OF THE INVENTION

[0008] These objects and others which will become apparent hereinafter are attained, in accordance with the invention in a method of accordion folding a continuous web of foldable material having a succession of equidistant grooves formed therein and separating panels of the web from one another. The method comprises the steps of:

[0009] (a) advancing the web longitudinally at a speed of advance;

[0010] (b) lifting the web in a region of each second groove, advancing the second groove at a speed matched to the speed of advance to forcibly fold the web at the second groove, and depositing a fold formed in the web at the second groove; and

[0011] (c) repeating step (b) after depositing each fold formed therein to collect the web as an accordion-folded set of the panels.

[0012] The web can be lifted exactly at each second groove or only in the region thereof. The entrainer or lifter can extend across the web and can be a wire or strand engaged at its ends in rollers or like members traveling in guides at opposite sides of the web. Important to the invention is that, as the web is advanced along its path, each second groove is lifted along a linear, upwardly inclined path to a peak height and then, in the form of a fold between the leading panels and the trailing panel, at the respective second groove, is brought down again toward the original path or plane of the web so as to fold two panels one over the other and deposit an accordion-folded product. The downward path is preferably a circular arc segment.

BRIEF DESCRIPTION OF THE DRAWING

[0013] The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

[0014]FIG. 1 is a diagrammatic side elevation of an apparatus for carrying out the method of the invention;

[0015]FIG. 2 is an illustration of an lifter or entrainer which is engageable with the web for folding same;

[0016]FIG. 3 is a diagram illustrating the invention;

[0017]FIG. 4 is a cross sectional view through the web;

[0018]FIG. 5 is a diagram showing the guide system for the arc segmental phase of the movement of the lifter or entrainer; and

[0019]FIG. 6 is a view similar to FIG. 5 of another guide arrangement.

SPECIFIC DESCRIPTION

[0020] The foldable material is fed in the direction of the arrow 1 as an endless or continuous web with certain speed in the direction of advance. That displacement can be continuous or discontinuous and the means for displacing the web can be a conveyor or drive system represented at 45 in FIG. 1.

[0021] The web can be fed along a guide 2 to an abutment 3 and two positions of the guide and abutment are shown at 2 and 3 in FIG. 1 or at 2 a and 3 a in FIG. 1 to indicate that the guide and abutment may be height adjustable.

[0022] As can be seen from FIG. 4, for example, the web 10 may be a corrugated paper sheet which can comprise a core 11 which can be of corrugated paper, sandwiched between cover sheets 12 and 13. Panels 14 and 15 are separated along the web 10 by grooves 16 formed in the web. As can be seen from FIG. 3, the grooves 16 may be located equidistantly from one another to define the panels 14 and 15, for example, between them. When one of these grooves, for example, the groove represented at 16′ in FIG. 3, is lifted by a lifter or entrainer represented at 20 and, as the web continues to move to the left in FIG. 3, this groove is initially guided upwardly in a linear path to a peak height and then is lowered along a circular arc segmental portion of the path, an accordion-folded stack can be formed as shown at 17 in FIG. 3.

[0023] In FIG. 2, the lifter or entrainer is shown as a member 48 which is in tension between two rollers 49 guided in sheet metal channels 47 on opposite sides of the web.

[0024] In other words, along the opposite sides of the web, guides 4 are provided which are spanned by the lifter 48 and can be the rollers 49 which are chained together in endless chains. The pair of these endless chains may define an initial straight line upward inclination 41 for the entrainer or lifter which transitions to an approximately circular arc segmental path 42. The lifters are then returned to their starting points over the linear segments 43.

[0025] With this form of guiding, each second groove is lifted in the region of the groove generally or exactly at the groove and automatically is forcibly folded until it is laid down again in the accordion-folded stack. During the movement of the circular arc segmental section 42, the two panels ahead of and behind the fold lie form an acute angle.

[0026] The spacing of the lifters or entrainers 48 in their respective conveyor chain can be variable to accommodate different fold lengths and the positions of the two guides can be varied as well to accommodate different widths of the web. The guides during the arcuate movement can be crossed arms 50 (FIG. 5) or rotary disks 51 (FIG. 6). 

We claim:
 1. A method of accordion folding a continuous web of foldable material having a succession of equidistant grooves formed therein and separating panels of said web from one another, said method comprising the steps of: (a) advancing said web longitudinally at a speed of advance; (b) lifting said web in a region of each second groove, advancing said second groove at a speed matched to said speed of advance to forcibly fold the web at said second groove, and depositing a fold formed in the web at the second groove; and (c) repeating step (b) after depositing each fold formed therein to collect said web as an accordion-folded set of said panels.
 2. The method defined in claim 1 wherein said web is lifted exactly at each second groove by an entrainer extending across the web.
 3. The method defined in claim 2 wherein said entrainer is initially displaced linearly and upwardly at an inclination to said web in a forward direction of travel thereof, and then said entrainer is displaced forwardly and downwardly.
 4. The method defined in claim 3 wherein said entrainer is displaced along a circular path during its displacement downwardly.
 5. The method defined in claim 1 wherein the fold is deposited along a circular arc-segmental path.
 6. An apparatus for accordion folding a continuous web of foldable material having a succession of equidistant grooves formed therein and separating panels of said web from one another, said web being advanced longitudinally at a speed of advance, said apparatus comprising a lifter engaging said web in a region of each second groove and a guide for said lifter formed on both sides of said web for lifting said web in said region of each second groove, advancing the respective second groove at a speed matched to the speed of advance to forcibly fold the web at each second groove and depositing the resulting fold formed at the second groove on a previously folded portion of said web.
 7. The apparatus defined in claim 6 wherein the guide formed on each side of said web is a chain.
 8. The apparatus defined in claim 7 wherein said lifter is a wire extending across said web.
 9. The apparatus defined in claim 6 wherein said guide includes a sheet metal member on each said of said web, said lifter being guided in said sheet metal members.
 10. The apparatus defined in claim 9 wherein said lifter is carried by support rollers.
 11. The apparatus defined in claim 6 wherein said guide defines an upwardly inclined path for said lifter to a high point and then a generally circular arc segmental path from said high point downwardly.
 12. The apparatus defined in claim 11 wherein said arc segmental path is defined by a rotary arm or rotary disk arrangement.
 13. The apparatus defined in claim 6 wherein the spacing of lifters along said guide is variable.
 14. The apparatus defined in claim 6, further comprising a guide for said web provided with an abutment forming a stop for said web.
 15. The apparatus defined in claim 14 wherein said guide or said step are height adjustable.
 16. The method defined in claim 1 wherein said web is a paper.
 17. The method defined in claim 16 wherein said paper has a corrugated core with cover sheets on opposite sides thereof. 